urn:lsid:ibm.com:blogs:entries-84a1e68f-fa2b-4d83-a240-5f565e7d6248Mainframe Performance Topics with Martin Packer - Tags - r744flpn I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.03022015-07-10T16:02:39-04:00IBM Connections - Blogsurn:lsid:ibm.com:blogs:entry-c1abed63-9d71-42b5-a36f-b856898e3b66Self-Documenting Systems (Actually Coupling Facilities) - One Year OnMartinPacker11000094DHactivefalseComment Entriesapplication/atom+xml;type=entryLikestrue2012-11-17T05:40:00-05:002012-11-17T05:40:00-05:00<p>About a year ago I posted: <a href="https://www.ibm.com/developerworks/mydeveloperworks/blogs/MartinPacker/entry/a_small_step_for_rmf_a_giant_leap_for_self_documenting_systems27?lang=en">A Small Step For RMF, A Giant Leap For Self-Documenting Systems</a>.</p>
<p>A year on I've encountered some customer data that's made me go &quot;huh?&quot;, related to this.</p>
<p>In the referenced post I mentioned R744FLPN, the Coupling Facility's LPAR Number. For the first time I've seen data where the match - with SMF 70 Logical Partition Number (in Logical Partition Section) - doesn't work.</p>
<p>But that's because I misinterpreted R744FLPN: It's actually the <b>User Partition Identifier</b>. The difference, as I understand it is that Logical Partition Number can vary over time, as reconfiguration happens. Whereas the User Partition Identifier can be set and remain the same forever.(And apparently you need that for the CFRM Policy to work.)</p>
<p>Obviously I've fixed up my code - to use the User Partition ID in SMF 70 (again in the Logical Partition Section). And it's yielded an additional set of detail in my code that describes the LPARs on a machine. (Deciding whether to kick myself is "a dish best served cold". <img src="https://www.ibm.com/developerworks/community/blogs/images/smileys/smile.gif" class="smiley" alt=":-)" title=":-)" /></p>
<p>So it'll be interesting to see how people use User Partition ID (UPI). If you're using it perhaps you could let me know the scenario where you're finding it useful. And remember UPI is not just for Coupling Facility LPARs.</p>
<p>Another new aspect of self-documenting coupling facilities is described in <a href="https://www.ibm.com/developerworks/mydeveloperworks/blogs/MartinPacker/entry/system_zec12_cflevel_18_rmf_instrumentation_improvements?lang=en">System zEC12 CFLEVEL 18 RMF Instrumentation Improvements</a>. That is all about how CF <b>links</b> are getting better documented.</p>
<p>(And if you were wondering why I haven't blogged for a month it's because I've been extremely busy with customer engagements and speaking at the UKCMG 1-Day Meeting and GSE Annual Conference (both of which were thoroughly enjoyable). I'm beginning another big study - and this post is the result of the first thing I tripped over in <strong>their</strong> data.)
About a year ago I posted: A Small Step For RMF, A Giant Leap For Self-Documenting Systems . A year on I've encountered some customer data that's made me go &quot;huh?&quot;, related to this. In the referenced post I mentioned R744FLPN, the Coupling Facility's...014184urn:lsid:ibm.com:blogs:entries-84a1e68f-fa2b-4d83-a240-5f565e7d6248Mainframe Performance Topics with Martin Packer2015-07-10T16:02:39-04:00urn:lsid:ibm.com:blogs:entry-e621043d-d455-44ab-a78b-f628ba395f15A Small Step For RMF, A Giant Leap For Self-Documenting SystemsMartinPacker11000094DHactivefalseComment Entriesapplication/atom+xml;type=entryLikestrue2011-10-20T10:53:38-04:002011-10-20T10:53:38-04:00<div>I mentioned APAR <a href="http://www-01.ibm.com/support/docview.wss?rs=0&amp;uid=isg1OA21140">OA21140</a> before - <a href="https://www.ibm.com/developerworks/mydeveloperworks/blogs/MartinPacker/entry/channel_z_s_all_static_all_day_forever_ird_and_hiperdispatch6?lang=en_us">here</a>. It's quite an old APAR and so it will (in all likelihood) be on your systems.</div><div> <br /></div><div>I'd like to draw your attention to a subtle 1-byte field in the SMF 74 Subtype 4 (Coupling Facility Activity) record: R744FLPN. It's the partition number for the coupling facility. (If you've seen any one of several of my presentations I'll've talked about this field.)<br /></div><div> </div><div>Here's a problem <b>I</b> have but most of you <b>don't</b>: I try to build a picture of your systems just from SMF / RMF data. (Actually I've run into lots of customers who have almost the same problem. From a &quot;systems should be self-documenting&quot; standpoint, if nothing else.) Let's review what we have:<br /></div><div> </div><div><ul><li>SMF 70 Subtype 1 gives you lots of information about a machine, including the serial number and all the LPARs - all in gory detail.</li><li>SMF 74 Subtype 4 gives you lots of Coupling Facility information - again in gory detail.</li></ul></div><div>It's been my contention that if you put these two together good stuff can happen:<br /><br /><ul><li>You can get a true picture of the CPU performance of coupling facility, especially in the shared ICF engines case.</li><li>You can match the CF links to the CHPIDs from SMF Type 73 (not that the latter will give you much information).</li><li>You can identify what each of those LPARs that show up using resources in the ICF engine pool actually are.</li><li>In principle I can identify free CF memory that could be redeployed to other LPARs as needed.<br /></li></ul></div><div>Maybe the first of these is the most significant but, as you know, I like to show up in a customer having got quite close to their systems - not asking the questions I should've got the answers to from the data. So the next two are nice as well. I consider the fourth &quot;unfinished business&quot; as we don't have a complete picture of machine memory but it's still valid.<br /> <br />Today I finally exploited r744flpn to do the matching. So you might like to, too. I could even define a view across SMF 70 and 74-4 with a full set of matching keys now. Whoo hoo! <img src="https://www.ibm.com/developerworks/community/blogs/images/smileys/smile.gif" class="smiley" alt=":-)" title=":-)" /></div><div> </div><div>A long time ago I encountered a customer with multiple coupling facility LPARs whose names <b>didn't</b> match the coupling facility names. So I wrote some code that only worked in the &quot;1 coupling facility on a machine&quot; case: Fairly trivial code.<br /> <br />Then RMF added machine serial number, the number of dedicated and shared engines and the LPAR weights to the 74-4 record. This helped with a customer case where every CF LPAR had the same name - across multiple machines. (Why do people do that?) <img src="https://www.ibm.com/developerworks/community/blogs/images/smileys/smile.gif" class="smiley" alt=":-)" title=":-)" /></div><div> </div><div>But in asking them to do that I forgot one other thing: LPAR Number. So now OA21140 provides that and we can do a direct match (where the code doesn't have to do lots of special-case detective work).</div><div> </div><div>As I said, this APAR is quite old. Usually I like to take advantage of new data as soon as a customer sends me it. But I've been busy these past 2 years like never before. (You might've noticed that.) <img src="https://www.ibm.com/developerworks/community/blogs/images/smileys/smile.gif" class="smiley" alt=":-)" title=":-)" /> So, finally I have the change in my code in to take advantage of that. (And I still have the other code in place as a fallback.) It turned out to be a tiny change - that took me 15 minutes to code and about the same to test. You'd be amazed at what can get done in &quot;interstitial time&quot;. <img src="https://www.ibm.com/developerworks/community/blogs/images/smileys/smile.gif" class="smiley" alt=":-)" title=":-)" /></div><div> </div><div>All in a day's work for a Principal Systems Investigator (PSI). <img src="https://www.ibm.com/developerworks/community/blogs/images/smileys/smile.gif" class="smiley" alt=":-)" title=":-)" /> </div>I mentioned APAR OA21140 before - here . It's quite an old APAR and so it will (in all likelihood) be on your systems. I'd like to draw your attention to a subtle 1-byte field in the SMF 74 Subtype 4 (Coupling Facility Activity) record: R744FLPN. It's the...003210urn:lsid:ibm.com:blogs:entries-84a1e68f-fa2b-4d83-a240-5f565e7d6248Mainframe Performance Topics with Martin Packer2015-07-10T16:02:39-04:00